Eh, maybe… but I am reminded of the observation that if a single tweak could significantly enhance mental abilities, evolution would have probably given it to us already. I think Eliezer Yudkowsky has a longish piece to this effect (please forgive me if I am mis-remembering).
I wouldn't describe charisma as a "mental ability." Rather, IMHO, there's a tradeoff between the type of thinking that helps you "win" status and power in a socially-fraught scenario (i.e. playing the Game of Thrones); vs. the type of thinking that helps you come off as being a person your audience would like to take out for a beer.
Or, to go even further, people will like you more (find you more "charismatic") to the exact degree that their predictive model of your current mental processes—built up by observing you—doesn't involve you putting in that extra work to seek status and power. You get more charismatic by shutting mental processes off! (And then signalling that you've done so, by e.g. saying things that cost you status that you wouldn't say if you cared about status. Like people do when slightly drunk!)
Super charisma or other abilities in all members of a group could have negative reproductive consequences and reduce the genetic fitness of that configuration, even if it's available.
Then you might expect a balance where everyone has a low chance of expressing such a fenotype. I believe there are ideas that color-blindness has a benefit like this. The same with sickle-cell anemia.
Not in cases where the deficits caused by the tweak are compensated for by modern culture. For example, it could be that natural selection made learning hard for adult humans in order to preserve scant knowledge in prehistorical times. But now that we have written culture this may no longer be necessary or desirable.
better example: depression and anxiety probably could have been selected by evolution to keep you out of danger, but in the modern minimally dangerous world no one would choose to have those traits if they could avoid them.
> if a single tweak could significantly enhance mental abilities, evolution would have probably given it to us already
Only if the tweak were beneficial to humanity as a whole would we all have it. We have developed many traits (such as selflessness) that are not in our best interest, but are in the best interest of our society.
It is quite plausible that evolution has found that tweak, but has only given it to a small minority of people, much as it has only given autism to a small minority of people.
Evolution is not an endless race to a superior form: mother nature is content with "good enough". Many modern sharks arrived 100 million years ago while modern humans are believed to be 70,000 years old. Why? Sharks were good enough.
Humans are good enough now. Even weak people can survive just fine - even people with defective genes that would not survive enough to reproduce a century ago. Not only dumb people can survive but there are evidence they procreate a lot more than smart people.
Don't mistake the term evolution for selecting only intrinsically superior or ideal traits. What if humanity evolve to being dominantly near sighted because it is no longer a killer condition?
Does it even make sense to talk about "superior" or "ideal traits" in humans? People who like to talk about eugenics tend to end up wearing funny little hats and red arm bands (only half joking here). :-)
I used to care about the direction mankind is taking when I was younger. Now that I have way more years behind me than ahead - I will die soon and so will everyone I know - I could not care less. It may sound bitter but it is also liberating.
The last person to leave the planet please turn the lights off. Or don't. All I know is that I won't be here.
Are the people who are having lots of children that survive to adulthood today different in significant ways from the people who had lots of children who survived to adulthood 100 years ago?
Clearly, yes.
> Not only dumb people can survive but there are evidence they procreate a lot more than smart people.
If dumb people survive and procreate more than smart people, and if intelligence is hereditary, the human race will become dumber.
